Unit 4 PAL Flashcards
characteristics of animals
- multicellular eukaryotes
- no cell walls
- heterotrophic
- internal digestion
- movement
list 5 sources of information for the evolutionary relationships among animal groups
- fossils
- patterns of embryonic development
- morphology and physiology
- protein structure
- gene sequences
diploblastic
two tissue layers (ecto and endo)
triploblastic
three tissue layers (endo, ecto, meso)
protostome
mouth first
deuterostome
mouth second
coelomate
body cavity within mesoderm
acoelomate
no fluid filled body cavity
pseudocoelomate
have a body cavity, but not wrapped on both sides with mesoderm
why was segmentation beneficial?
- allowed for specialization of regions
- helped control movement
what role did locomotion play in the Cambrian explosion (“explosion of diversity”)
- beneficial for
- –finding food and mates
- –avoiding predators
- movement led to a huge increase in the need for energy which in turn led to predator-prey coevolution
what was the common ancestor of animals
-colonial flagellate protist
describe platyhelminthes
flatworms, dorsoventrally flattened, blind gut
describe rotifers
very small, complete gut, pseudocoel, cilia
describe bryozoan
moss animals, filter feeders, 1-2 mm, form colonies, sessile
describe brachiopods
- two part shells
- peaked in paleozoic and mesozoic (450 species left)
brachiopod shell
- two shell halves are dorsal and ventral
- resemble bivalve mollusks but shell is product of convergent evolution
what are the classes within phylum mollusca?
polyplacophora, gastropoda, bivalves, cephalopoda
polyplacophora
chitins
gastropoda
snails, slugs
bivalves
clams, oysters, scallops
cephalopoda
squids, octopuses, chambered nautilus
what is the visceral mass
mass containing heart, digestive, excretory, and reproductive
describe polyplacophora
chitins
- 8 calcareous plates (protection)
- marine
- use radula for feeding (scapes rocks)
- clings to rocks with muscular foot
describe gastropoda
snails and slugs
- some are toxic
- only mollusks that live in terrestrial habitat
describe bivalves
clams, oysters, scallops, and mussels
- 30,000 species
- hinged, two part shell, use foot to burrow into sand
- feed with siphon
describe siphon feeding
- water and food in through incurrent siphon
- water out through excurrent siphon
describe cephalopods
squids, octopus, chambered nautilus
- modified excurrent siphon
- eyes similar to vertebrates
- use arms and tentacles to capture food
- most retain small internal shell for support
- -pen
modified excurrent sipon allows for
jet propulsion
what are the classes within phylum annelida?
oligochaetes, polychaetes, hirudinea
oligochaetes
earthworms
polychaetes
mostly marine worms
hirudinea
leeches
describe oligochaetes
earthworms
- don’t have parapodia, eyes, or tentacles
- few setae
- burrow in and digest soil
- hermaphroditic
describe polychaetes
- marine
- burrowing
- parapodia on each segment
describe hirudinea
leeches
- lack parapodia
- no obvious segments
- suckers
list the unifying characteristics of ecdysozoans
- cuticle
- shed their cuticle to grow
- “molting” evolved only once
- all have single common ancestor
nematoda includes
roundworms and horsehair worms
how do ecdysozoans grow
molting
describe roundworms
- gas exchange through cuiticle
- moist environ
- abundant
- microscopic
- elphatiasis
describe horsehair worms
- thin
- can grow up to a meter long
- larvae are intestinal parasites of insects
describe tardigrades
water bears
- 8 fleshy legs
- live in sands and water films on plants and lichens
describe onchyophorans
velvet worms
- live in decomposing leaves in humid tropics
- resemble arthropod ancestors
describe arthropod exoskeleton
- cuticle
- made of chiton
- protects from dessication and predators
describe arthropods
- exoskeleton
- muscles attached to exoskeleton
- segmented
- jointed appendages
describe chelicerates (subphylum)
- merostomata (horseshoe crabs)
- arachnida (spiders, scorpions, ticks)
- mouthpart appendages (chelicerae)
- four pairs of walking legs
describe chelicerae
for grasping, inject venom
myriopods classes
- chilopoda
- diplopoda
myriopods have what instead of chelicerates
mandible
chilopoda
centipedes (2 leg/segment)
diplopoda
millipedes (4 leg/segment)
describe crustacea
marine, freshwater, and terrestrial
shrimp, lobster, crabs, and barnacles
describe hexapoda
class insecta, segmented, head has one pair of antennae, thorax has three pairs of legs and two sets of wings, abdomen doesn’t have appendages, nerve cord
